If one had to identify the key of the Interlude for an examination, what would it be? It has seven flats, but it is neither in C-Flat Major, nor in a-flat minor. There is an F-natural in the middle, but I don’t see it going to G-flat Major, nor eb minor either. I guess it is one of those church-type (Gregorian?) modes, but I have no idea which one? So is there a key for that modulation too? Can anybody help? Please. If so, please advise how it was identified.